Biology of the Bumpytail Ragged-

Tooth Shark
(Odontaspis ferox)

Field Marks

Second dorsal and anal fins smaller than first dorsal fin; first dorsal
fin origin closer to pectoral fin bases than pelvic bases; snout bulbously
conical relatively long (greater than mouth width); teeth slender and
fang-like, usually with 2 or more lateral cusplets on each side of main
blade; 2 large anterior teeth on each side of upper jaw, separated from
lateral teeth by 2 to 5 small intermediate teeth; Color medium to dark
grey above, belly often blotched; young with dusky margins and tips on
both dorsal fins and caudal fin, sometimes with darker reddish spots
scattered on flanks.

Size

Length at birth predicted to be about 41 in (105 cm); average length 5
to 7 ft (1.5 to 2.1 m); maximum size is 12 ft (3.7 m) in length and 710 lb
(323 kg) for a female specimen; largest recorded male was 9 ft (2.75 m)
long.

Range

Cosmopolitan but spottily distributed.

Habitat

Deep-water inhabitant of warm temperate and tropical seas; on or near
the bottom on continental or insular shelves and upper slopes (has been
observed by divers on coral and rocky reefs near drop offs), but also
occurs in open ocean; known depth range 43-1,380 ft (13 to 420 m), but
possibly as deep as 1 740 ft (530 m) off New Zealand; a specimen was
recently caught at a depth of 33-140 ft (10-40 m) in the Sicilian Channel,
elsewhere most are caught at depths of 43-300 ft (13-91 m).

Feeding

Preys on small teleosts, other elasmobranchs (off southern California,
parts of an unidentified ray were observed falling from the mouth of a
captured individual), squids, shrimps and other crustaceans (there is an
odd reference to a "pillbug" found among the stomach contents of
a specimen from southeastern Australia); has been observed swimming amid
large groups of baitfish.

Males reach sexual maturity at a length of about 9 ft (2.75 m), females
at about 12 ft (3.6 m); no data on age at maturity or longevity for either
sex.

Danger to Humans

Potentially dangerous, but has not been implicated in attacks on humans;
has on rare occasion been observed by divers, showing no aggression toward
them even when approached closely (a large, free-swimming individual was
recently photographed underwater in the western Mediterranean)

Utilization

Most catches are accidental in gill nets set close to the bottom; an
infrequent bycatch in the Sea of Cortez shark fishery, also caught
sporadically by setlines off south-west Malta, mostly at night over rocky
bottoms at depths of 130-660 ft (40-200 m); in Japan, oil and meat from
this species considered inferior to that of the Sandtiger (Carcharias
taurus).

Remarks

Poorly known shark that may be far more wide-ranging in warm-temperate
and tropical seas than current records indicate and seasonally abundant in
some regions; confusion with other sharks may be partly to blame for the
general lack of biological data on this species; catches should be
preserved and reported.

There are few things new under the terrestrial sun. But such is definitely
not the case in the ocean. One of the most unique and seductive qualities of
recreational scuba diving is that virtually any individual applying keen powers
of observation and an enquiring turn of mind can see things that no one has
before. In doing so, divers can even make fundamental scientific discoveries
about the natural world in a manner afforded by few other sports activities.

The Bumpytail Ragged-Tooth Shark is widely distributed, but records of its occurrences
are so few and spotty it is all-but impossible to predict where one will next
appear. It is typically a deep-water species that is most active at night. As a
result, it is rarely seen alive and very little is known of its behavior in the
wild. In August 1998, shark biologist Ian Fergusson received via modem what are
almost certainly the first underwater photographs of a free-swimming Bumpytail Ragged-Tooth
Shark. Taken by Lebanese scuba instructor Walid Noshie in 1993, the
photos show that — unlike the flabby, distorted, faded, and very dead specimens
pictured from time-to-time in the scientific literature — the living Bumpytail Ragged-Tooth
is a gorgeous creature indeed: sleek and solid, with graceful
lines; its body is a handsome charcoal-grey above, shading smoothly to pure
white below; and its face is punctuated by spectacular slender teeth and dark,
soulful eyes. At long last, it is clear that the Bumpytail Ragged-Tooth Shark is every bit
as photogenic as it's better-known cousin, the Sandtiger (Carcharias taurus).

According to Walid Noshi, he and other divers have encountered small
aggregations of 11.5- to 13-foot (3.5- to 4- metre) Bumpytail Ragged-Tooth Sharks at the
same dive site almost every summer (July-August) since 1979. This locally
renowned dive site is called "Shark World", located some 0.6 to 2
miles (1 to 3 kilometres) off the coast of Beirut. The underwater terrain there
consists of rocky reef areas and terraces ranging in depth from about 100 to 150
feet (30 to 45 metres), with associated deeper drop-offs and some nearby wrecks.
The sharks themselves are neither particularly curious nor aggressive toward
divers. Thus, unless provoked, the Bumpytail Ragged-Tooths probably do not represent a
significant threat to humans. Given the significant depths involved, however,
this is clearly not a dive for the inexperienced or faint-of-heart. But the
opportunity to encounter the rare and little-known Bumpytail Ragged-Tooth Shark must be
highly seductive to any diving naturalist.

Why do small aggregations of Bumpytail Ragged-Tooth Sharks visit the "Shark
World" dive site each summer? Where do they go during the rest of the year,
and why? With very limited information to go on, it is difficult to answer such
questions. Captures made during early morning and late evening in the Indian
Ocean suggest that the Bumpytail Ragged-Tooth Shark may be a vertical migrator, ascending
into shallower water at night and returning to the depths before dawn. The
nearby drop-offs at "Shark World" may allow these generally deep-water
sharks access to the rich feeding afforded by the relatively shallow rocky reefs
and terraces at "Shark World". Unfortunately, the diet of the Bumpytail Ragged-Tooth
in the Mediterranean — as elsewhere — is very poorly known. The
teeth of this species are less robust and more weakly differentiated than those
of its better-known cousin, the Sandtiger. Thus, the Bumpytail Ragged-Tooth probably feeds
primarily on small bony fishes, but may also take squids and shrimps when the
opportunity presents itself. Unfortunately, feeding is only very rarely
witnessed in the wild — not because it particularly infrequent, but largely
because predation events tend to occur with explosive suddenness. Afterward,
particularly in marine habitats, everything returns to 'normal' with deceptive
rapidity. Unless a diver happens to be looking in the right direction at the
right time, he or she would probably never know anything important had happened.

The reported size of the sharks encountered at the "Shark World"
site fall well within the range for sexually mature Bumpytail Ragged-Tooth Sharks
— males
mature at a length of about 9 ft (2.75 m), females at about 12 ft (3.6 m). Since
the Bumpytail Ragged-Tooths encountered at "Shark World" include members of both
sexes and some individual females bear indistinct scarring on their flanks,
fins, and backs, Ian Fergusson and Leonard J.V. Compagno speculate that — rather
than being primarily a feeding area — the site may represent a mating ground for
this species in the eastern Mediterranean. If, however, underwater observations
at night confirm that the Bumpytail Ragged-Tooths at "Shark World" actively
feed, Fergusson and Compagno may revise their conclusion. Alternatively, perhaps
further evidence of Bumpytail Ragged-Tooth reproductive activity will eventually be found
at "Shark World": signs of fresh, white mating scars on females or
perhaps an as-yet undiscovered shallow-water nursery area (where the 3-foot or
1-metre pups are born), just shoreward of the "Shark World" site. Such
discoveries, as well as accounts of encounters with Bumpytail Ragged-Tooth Sharks from
here or elsewhere on the globe, should be reported to an ichthyologist or other
marine researcher, especially one with a particular interest in sharks.

Not that long ago, the chief prizes with which divers could return to the
surface were food, hunting trophies, or tall tales of undersea adventure. There
is still adventure aplenty to be had in the ocean, but for many divers the
nature of the prizes to be brought back has changed dramatically. Armed with an
understanding of what to look for and by carefully reporting and recording their
underwater discoveries, divers are in a powerful position to significantly
increase our understanding of not only rare or unusual sharks, but of the ocean
in general. There are few adventures that can offer such rich rewards.